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The following is a summary of “Fatty Infiltration Predicts Retear And Functional Impairment Following Rotator Cuff Repair: Systematic Review And Meta-Analysis,” published in the March 2025 issue of the Journal of Orthopaedic Surgery and Research by Wu et al.

Fatty infiltration (FI) of the rotator cuff (RC) muscles is frequently observed in patients with full-thickness RC tears, yet its prognostic significance remains a subject of debate, particularly in cases of moderate to severe FI. This systematic review and meta-analysis aim to comprehensively assess the relationship between preoperative FI severity and the risk of postoperative retear, as well as its association with functional outcomes following complete RC repair. A systematic literature search was conducted using PubMed, Embase, and Web of Science to identify studies evaluating the impact of FI, classified using the Goutallier classification and the global fatty degeneration index (GFDI), on postoperative outcomes. Meta-analysis was performed to determine the ORs for retear among patients with mild (grade 0–1), moderate (grade 2), and severe (grade 3–4) FI. 

Qualitative synthesis was also conducted to examine the association between FI and functional recovery. A total of 18 studies comprising 1,997 patients were included in the systematic review, while 10 studies were eligible for meta-analysis. The analysis revealed that patients with a GFDI ≤ 1 exhibited significantly lower odds of retear (OR = 0.08, 95% CI 0.02–0.29, p < 0.01). In the supraspinatus muscle (SSP), moderate FI was associated with an increased risk of retear compared to mild FI (OR = 1.95, 95% CI 1.09–3.48, p = 0.02), while severe FI further elevated the risk relative to moderate FI (OR = 3.37, 95% CI 1.08–10.53, p = 0.04). Similar trends were observed in the infraspinatus muscle (ISP), with moderate FI linked to a higher retear risk than mild FI (OR = 2.22, 95% CI 1.07–4.62, p = 0.03) and severe FI further increasing the likelihood of retear (OR = 2.06, 95% CI 1.02–4.16, p = 0.04). 

However, FI severity in the subscapularis and teres minor muscles did not exhibit a significant association with retear rates. Regarding functional recovery, lower FI grades in the GFDI were consistently associated with superior postoperative outcomes, whereas FI severity in individual muscles did not demonstrate a significant correlation with functional prognosis. These findings suggest that FI severity, particularly in the SSP and ISP, is a critical factor influencing the risk of structural failure following RC repair. Additionally, GFDI serves as a reliable predictor of both anatomic and functional impairments, reinforcing its potential utility in preoperative risk stratification.

Source: josr-online.biomedcentral.com/articles/10.1186/s13018-025-05702-6